Description: (Applicant?s Description) The Crystallography Facility offers the capability for determination of the crystal structure of small molecules (e.g., peptides or ligands), as well as macromolecules (i.e., proteins or nucleic acids). Crystals produced by individual research groups are tested for diffraction and analyzed for the extent of diffraction resolution. X-ray diffraction data are collected by diffractometer measurements for small molecules and by multiwire area detectors or imaging plate detectors for macromolecules. The crystallographers affiliated with the Crystallography Facility interact directly with users to devise strategies to determine the crystal structures of interesting molecules. This information is critical to the ongoing research of a number of Institute projects. The Crystallography Facility is used by four-five laboratories at the Cancer Center. In addition, crystallographic studies are planned in the research programs of three-four other members of the Cancer Center, and experiments are underway to purify and crystallize the candidate molecules. In the coming year, it is expected that usage of this facility will increase significantly with the recruitment of additional crystallographers to the Cancer Center.